Just weeks after they became Instagram official, Taylor Swift and Calvin Harris are now Twitter official too.

Calvin, 31, tweeted his support to "my girl" Taylor, 25, after her game-changing open letter to Apple Music prompted the streaming service to change its royalties policy for artists.

The "my girl" part is pretty clear, but if you're confused about the owl reference, that was the stage set-up for the Scottish DJ's latest gig at the Electric Daisy Carnival in Las Vegas.

Taylor favourited the tweet, so there's no shaking this one off anytime soon.

The 'Bad Blood' singer took on Apple Music for its policy of not paying artists during the free, three-month trial period for users. In a Tumblr note, Taylor outlined why she wouldn't let her 1989 album be streamed on the service because "it is unfair to ask anyone to work for nothing".

"These are not the complaints of a spoiled, petulant child," she wrote. "These are the echoed sentiments of every artist, writer and producer in my social circles who are afraid to speak up publicly because we admire and respect Apple so much. We simply do not respect this particular call."

Apple Music Senior Vice President Eddy Cue called Taylor personally to announce the policy change. Here's how she responded: